Battery Cell Replacement Availability UK

[MickeyS70]

Are these 60Ah cells worth trying?

A complete 88 pack replacement with 60Ah cells was unsuccessful (although unclear as to why) see link in one of my previous posts.

The jury is still out if one could use 94Ah NMCs without the need for a BMU hack but it certainly works when modified.

Mickey

 

[kiev]

From a PM:

...idea of replacing a whole battery here. Do you know if there 's a way to replace them 1-1 without replacing them to LEV batteries and/or making changes in the BMU?

As far as i know there is no drop-in cell with the same volume, terminals, and CMU attachment as the LEV cells.
Also the BMU Reset allows quicker access to the original capacity rather than waiting for possible incremental +1Ahr per charging cycle increases. The car will still think it has a degraded capacity and will go into Turtle mode and limit the useful range.

 

[riburada]

So its pretty much straight forward - replace the cells and gain access to the BMU stating that you have changed the cells and the capacity from now on is as follows... right?

 

[kiev]

That is my understanding--the Reset procedure is just like replacing a pack with a new one to get the original range back.

The mechanical fitment--size of cells, addition of spacers, CMU cell connections, terminal fasteners and buss bars, etc. may not be quite as simple. May need to find or create solutions for some of the hardware issues.

These are my thoughts based upon conversations with Piev Paul after he re-built and did this to his own pack.

 

[MickeyS70]

That is my understanding--the Reset procedure is just like replacing a pack with a new one to get the original range.

From memory Piev Paul’s approach required a BMU hack first (to increase the battery capacity to 94Ah) before he did a battery reset with MUT.

Leaving out this step will set the max capacity to 45Ah and your original range is restored initially, however the question is how the BMU is interpreting the different chemistry (and mismatch capacity value) during a recommended battery calibration procedure:

a) no different than with original cells, i.e capacity will actually increase in 1A steps to a max of 65Ah

b) the capacity constantly decreases in 1A steps as charge curve is different

c) the calibration doesn’t work at all and degradation follows standard BMU algorithm

d) BMU gets confused altogether and performance/range drop to below useful levels

e) ???

I suppose the only way we’ll find out for certain if someone is curious or desperate enough to ‘try this at home’…
Mickey

 

[riburada]

Yeah well... there isn't that much money into it. The full amount of cells needed to construct the whole pack cost some 2500€. The only thing that's a bit worrying for me is the BMU side - if the BMU does not recognize the batteries at once after replacement. T h a t may be a time consuming effort.

 

[MickeyS70]

The only thing that's a bit worrying for me is the BMU side - if the BMU does not recognize the batteries at once after replacement.

I have come round to the idea that it is actually possible to upgrade to 60Ah NMC cells without a BMU hack if you

- can reset the battery capacity to 45Ah via MUT/Diagbox
- prevent the ‘native’ battery calibration procedure to take place
- make sure you stay above a cell voltage of 2.8V at all times
- limit Rapid (DC) charge to 38KWh
- are happy to accept that at best original range is restored

Mickey

 

[riburada]

Good, thanks for rooting to the topic

The only thing that's a bit worrying for me is the BMU side - if the BMU does not recognize the batteries at once after replacement.

I have come round to the idea that it is actually possible to upgrade to 60Ah NMC cells without a BMU hack if you

- can reset the battery capacity to 45Ah via MUT/Diagbox
- prevent the ‘native’ battery calibration procedure to take place
- make sure you stay above a cell voltage of 2.8V at all times
- limit Rapid (DC) charge to 38KWh
- are happy to accept that at best original range is restored

Mickey

I think the most reasonable thing is to replace just the whole pack with 50Ah cells, as it was and gain back the original range

 

[coulomb]

... the most reasonable thing is to replace just the whole pack with 50Ah cells, as it was ...

But where to find these compatible 50 Ah cells?

 

[riburada]

... the most reasonable thing is to replace just the whole pack with 50Ah cells, as it was ...

But where to find these compatible 50 Ah cells?

China naturally

 

[stoatwblr]

It need more then just cappacity changed . A man in Rusia reserch his pack from 2019 to 2021 when he sucseed to to change his BMS firmware to read and charge this cells normal . He change my firmware via remote controled laptop . I need to by only original Tactrix open port and instal MUT 3 on laptop .And to pay him for this servise . I am verry happy that find that man

I contacted this Russian gentleman some time ago regarding his BMU reprogramming. He said he had never laid eyes on the physical installation

I'm assuming that means you're the builder and you have some documentation/photos of what you did?

A lot of people would like to see how you did it...

 

[stoatwblr]

This is great information. Thanks for finding it. I've noticed that new NMC cells have a max voltage of 4.3 volts. If the nominal capacity is at 4.3 volts then our capacity will be lower when the BMU in our car only charges the battery to 4.1 volts. But then charging to 4.3 volts will obviously shorten the life of the new battery.

On the other hand, I don't think we should not give up hope yet.

NMCs have a considerably different (dis)charge curve to LEV50s (the maximum voltage for LEV50s is 4.2V, it's limited to 4.1V to preserve their lifespan)

This results not only in not being fully charged but the BMU declares the cells "discharged" (by LEV50 standards) when they still have about ~40% capacity left

This is why Daneto and Kiev have used reprogrammed BMU/ CAN MITM modules

My personal opinion: I'd prefer to use LiFePo4 cells and take the voltage hit, as these have better durability and vastly lower fire risk if things go wrong. It's clear the cars can cope with lower cell and pack voltages - as seen by the 80-cell PSA versions and (JDM) lithium-titanate packs

 

[stoatwblr]

To do a MUT RESET as the dealership service tech does for a replaced pack

This can be done with HobDrive. Hobdrive also enables access to the "learn capacity" cycle (meaning you'll see your ACTUAL available capacity immediately instead of it incrementing/decrementing by 1Ah per few hundred km or so)

NB: "Learn capacity" requires being plugged into a slow charger. It will discharge the pack to threshold values (turn the heater and AC on full blast, windows down) and then initiate a charge cycle to perform the calibration. It takes 6-12 hours depending on the condition of your pack and it's best to run capacity down to 3-4 bars before starting the process or you'll be waiting even longer

 

[Daneto1978]

Yes i have some picks and video , but it is too long video .Make everything slow and carefool . Soon will open battery pack to get one cell out , and will attach it to battery tester i have to see how much realy loosing capacity.Already make 11000 km from upgrade . I am think that bms algorithm is not good and show me worse results as it is in reality. Have 2 spare cells so can make comparision between them .

 

[suziauto]

We are looking for a workshop in the UK to be an Installer of our 30Kw Imiev kits.. should be compatable with the 80 cell versions as well. These are very complicated so we will only supply via an authorised installer/workshop.

I f anyone wants to refer someone to apply please get them to contact us at www.ozelectricvehicles.com thanks

 

[stoatwblr]

Good to see you here, Suziauto. Have you considered contracting Kolyandex to rewrite the BMU rather than using the MITM solution?

 

[suziauto]

Good to see you here, Suziauto. Have you considered contracting Kolyandex to rewrite the BMU rather than using the MITM solution?

theres more we can do with our VCU so future upgrades may come online .. at the moment we are flat out redesigning a solution for Leaf and have 2 cars in beta testing.. and the Mitsubishi Outlander upgrade is just finished this week so that should roll out soon.

 

[Gary12345]

Shame I didnt see this before - Cleevely EVs in Cheltenham UK have a stock of cells and many Hevra garages across the UK can get the cells from Cleevely and swap them out. Im based in the UK and have fixed several i-mievs (plus Citroen C-Zero and Peugeot ion as they were also branded here) by replacing cells, replacing CMU circuit boards in the pack, etc. Cheers

http://www.hevra.org.uk

 

[MickeyS70]

Shame I didnt see this before - Cleevely EVs in Cheltenham UK have a stock of cells and many Hevra garages across the UK can get the cells from Cleevely and swap them out. Im based in the UK and have fixed several i-mievs (plus Citroen C-Zero and Peugeot ion as they were also branded here) by replacing cells, replacing CMU circuit boards in the pack, etc. Cheers

http://www.hevra.org.uk

Good to hear, however the issue with 10 + year old triplets is that they generally only have bad and worse cells at this stage and once you start replacing you need to keep going I’m afraid…